Hydrangea plant named ‘HP217901’

ABSTRACT

A new and distinct cultivar of Hydrangea plant named ‘HP217901’, characterized by its compact, upright to somewhat outwardly spreading and rounded plant habit; moderately vigorous growth habit and rapid growth rate; freely branching habit with strong, thick and sturdy stems; early, freely and uniformly flowering habit; pyramidal inflorescences with numerous light yellow green-colored sterile flowers; and good garden performance.

Botanical designation: Hydrangea paniculata.

Cultivar denomination: ‘HP217901’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea plant, botanically known as Hydrangea paniculata, commercially referred to as a panicle Hydrangea and hereinafter referred to by the name ‘HP217901’.

The new Hydrangea plant is a product of a planned breeding program conducted by the Inventor in De Kwakel, The Netherlands and Lengerich, Germany. The objective of the breeding program was to create new compact and freely-branching Hydrangea plants with strong sturdy stems, large inflorescences with numerous showy sterile flowers, attractive sterile flower color and good garden performance.

The new Hydrangea plant originated from a cross-pollination made by the Inventor in August, 2010 in De Kwakel, The Netherlands, of a proprietary selection of Hydrangea paniculata identified as code number 11-0003, not patented, as the female, or seed, parent with a proprietary selection of Hydrangea paniculata identified as code number 11-0006, not patented, as the male, or pollen, patent. The new Hydrangea plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in Lengerich, Germany in September, 2012.

Asexual reproduction of the new Hydrangea plant by vegetative tip cuttings in a controlled environment in De Kwakel, The Netherlands since March, 2014 has shown that the unique features of this new Hydrangea plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘HP217901’. These characteristics in combination distinguish ‘HP217901’ as a new and distinct Hydrangea plant:

-   -   1. Compact, upright to somewhat outwardly spreading and rounded         plant habit.     -   2. Moderately vigorous growth habit and rapid growth rate.     -   3. Freely branching habit with strong, thick and sturdy stems.     -   4. Early, freely and uniformly flowering habit.     -   5. Pyramidal inflorescences with numerous light yellow         green-colored sterile flowers.     -   6. Good garden performance.

Plants of the new Hydrangea can be compared to plants of the female parent selection. Plants of the new Hydrangea differ primarily from plants of the female parent selection in plant habit as plants of the new Hydrangea are more compact than plants of the female parent selection. In addition, plants of the new Hydrangea flower earlier than plants of the female parent selection.

Plants of the new Hydrangea can be compared to plants of the male parent selection. Plants of the new Hydrangea differ primarily from plants of the male parent selection in plant habit as plants of the new Hydrangea are more compact than plants of the male parent selection. In addition, plants of the new Hydrangea and the male parent selection differ in sterile flower color as sterile flowers of plants of the male parent selection become red in color with aging.

Plants of the new Hydrangea can be compared to plants of the Hydrangea paniculata ‘Limelight’, disclosed in U.S. Plant Pat. No. 12,874. In side-by-side comparisons, plants of the new Hydrangea differ primarily from plants of ‘Limelight’ in the following characteristics:

-   -   1. Plants of the new Hydrangea are more compact than plants of         ‘Limelight’.     -   2. Plants of the new Hydrangea have a more rapid growth rate and         flower about three weeks earlier than plants of ‘Limelight’.     -   3. Plants of the new Hydrangea are more freely branching than         plants of ‘Limelight’.     -   4. Panicles of plants of the new Hydrangea are smaller than         panicles of plants of ‘Limelight’.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance of the new Hydrangea plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description which accurately describe the colors of the new Hydrangea plant.

The photograph on the first sheet is a side perspective view of a typical flowering plant of ‘HP217901’.

The photograph on the second sheet is a top perspective view of a typical flowering plant of ‘HP217901’.

The photograph on the third sheet is a close-up view of a typical inflorescence of ‘HP217901’.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the following description were grown during the late summer in 22-cm containers in an outdoor nursery in Lengerich, Germany and under cultural practices typical of commercial panicle Hydrangea production. During the production of the plants, day and night temperatures averaged 15° C. Plants of the new Hydrangea 18 months old when the photographs and description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea paniculata ‘HP217901’. -   Parentage:     -   -   Female, or seed, parent.—Proprietary selection of Hydrangea             paniculata identified as code number 11-0003, not patented.         -   Male, or pollen, parent.—Proprietary selection of Hydrangea             paniculata identified as code number 11-0006, not patented. -   Propagation:     -   -   Type cutting.—By vegetative tip cuttings.         -   Time to initiate roots, summer.—About two weeks at             temperatures about 23° C.         -   Time to initiate roots, winter.—About 18 days at             temperatures about 18° C.         -   Time to produce a rooted young plant, summer.—About four             weeks at temperatures about 23° C.         -   Time to produce a rooted young plant, winter.—About five             weeks at temperatures about 18° C.         -   Root description.—Thick; typically whitish brown in color,             actual color of the roots is dependent on substrate             composition, water quality, fertilizer type and formulation,             substrate temperature and physiological age of roots.         -   Rooting habit.—Freely branching; dense. -   Plant description:     -   -   Plant and growth habit.—Compact, upright to somewhat             outwardly spreading and rounded plant habit; strong and             sturdy stems; rapid growth rate and moderately vigorous             growth habit.         -   Plant height.—About 50 cm.         -   Plant diameter or area of spread.—About 60 cm to 70 cm. -   Lateral branch description:     -   -   Branching habit.—Freely branching habit; when pinched, about             25 to 30 lateral branches develop per plant.         -   Length.—About 35 cm to 40 cm.         -   Diameter.—About 4 mm.         -   Internode length.—About 4 cm.         -   Texture.—Smooth, glabrous; fully developed, woody.         -   Aspect.—Upright to almost horizontal.         -   Strength.—Strong, sturdy.         -   Color.—When developing: Close to 143C; lenticels, close to             165C. Developed: Close to 177B; lenticels, close to 165C. -   Leaf description:     -   -   Arrangement.—Opposite, simple.         -   Length.—About 7 cm to 8 cm.         -   Width.—About 4.2 cm to 5 cm.         -   Shape.—Ovate.         -   Apex.—Acute.         -   Base.—Obtuse.         -   Margin.—Serrulate.         -   Texture, upper surface.—Rugose; pubescent.         -   Texture, lower surface.—Prominent venation; glabrous.         -   Venation pattern.—Pinnate.         -   Color.—Developing and fully developed leaves, upper surface:             Close to 143B; venation, close to 145A. Developing and fully             developed leaves, lower surface: Close to 138B; venation,             close to 145C.         -   Petioles.—Length: About 1 cm to 1.8 cm. Diameter: About 2 mm             to 3 mm. Texture, upper and lower surfaces: Smooth,             glabrous. Color, upper surface: Close to 145B. Color, lower             surface: Close to 145C tinged with close to 178B. -   Flower description:     -   -   Flower type and habit.—Showy sterile flowers and small             fertile flowers arranged on terminal panicles; panicles             pyramidal in shape; flowers face upright to outwardly             depending on their position in the inflorescence.         -   Fragrance.—None detected.         -   Natural flowering season.—Early flowering habit, plants             begin flowering about 15 weeks after planting; flowering             begins in the early summer and is continuous throughout the             summer in Northern Europe.         -   Flower longevity.—Fertile flowers last about one month on             the plant, fertile flowers not persistent; sterile flowers             last about three months on the plant, sterile flowers             persistent.         -   Quantity of flowers.—Freely flowering habit; about 200             fertile flowers per panicle and about 250 to 400 sterile             flowers per panicle.         -   Panicle height.—About 10 cm to 12 cm.         -   Panicle diameter.—About 10 cm to 12 cm.         -   Fertile flower buds.—Length: About 2 mm. Diameter: About             2 mm. Shape: Rounded. Color: Close to 145C.         -   Sterile flower buds.—Length: About 2 mm. Diameter: About             2 mm. Shape: Rounded. Color: Close to 145C shaded with close             to 181D.         -   Fertile flower diameter.—About 3 mm to 4 mm.         -   Fertile flower depth (height).—About 3 mm.         -   Sterile flower diameter.—About 3 cm.         -   Sterile flower depth (height).—About 2 cm.         -   Petals, fertile flowers.—Quantity and arrangement: About             four or five in a single whorl. Length: About 2 mm to 3 mm.             Width: About 1 mm to 2 mm. Shape: Ovate. Apex: Acute. Base:             Cuneate. Margin: Entire. Texture, upper and lower surfaces:             Smooth, glabrous. Color: When opening, upper and lower             surfaces: Close to 157D. Fully opened, upper and lower             surfaces: Close to 157D; color does not change with             development.         -   Petals, sterile flowers.—Quantity and arrangement: About             four or five in a single whorl. Length: About 2 mm. Width:             About 2 mm. Shape: Ovate. Apex: Acute. Base: Cuneate.             Margin: Entire. Texture, upper and lower surfaces: Smooth,             glabrous. Color: When opening, upper and lower surfaces:             Close to 157D. Fully opened, upper and lower surfaces: Close             to 157D; color does not change with development.         -   Sepals, fertile flowers.—Quantity and arrangement: About             four or five in a single whorl. Length: About 1 mm. Width:             About 1 mm. Shape: Ovate. Apex: Acute. Base: Obtuse. Margin:             Entire. Texture, upper and lower surfaces: Smooth, glabrous.             Color: When opening, upper and lower surfaces: Close to             145B. Fully opened, upper and lower surfaces: Close to 145C;             color does not change with development.         -   Sepals, sterile flowers.—Quantity and arrangement: About             four to five in a single whorl; slightly imbricate. Length:             About 1.6 cm to 1.8 cm. Width: About 1.4 cm to 1.6 cm.             Shape: Ovate. Apex: Obtuse, slightly retuse. Base: Cuneate.             Margin: Entire. Texture, upper and lower surfaces: Smooth,             glabrous. Color: When opening, upper surface: Close to 145B.             When opening, lower surface: Close to 145C. Fully opened,             upper surface: Close to 145C; color does not change with             development. Fully opened, lower surface: Close to 145D;             color does not change with development.         -   Pedicels, fertile flowers.—Length: About 3 mm. Diameter:             About 1 mm. Strength: Strong. Aspect: Mostly upright.             Texture: Smooth, glabrous. Color: Close to 145C.         -   Pedicels, sterile flowers.—Length: About 1.5 cm to 2 cm.             Diameter: About 1 mm to 1.5 mm. Strength: Strong. Aspect:             About 80° to 90° from branch axis. Texture: Smooth,             glabrous. Color: Close to 145D.         -   Reproductive organs, fertile flowers.—Stamens: Quantity per             flower: About nine to ten. Filament length: About 3 mm.             Filament color: Close to 157D. Anther length: About 1 mm.             Anther shape: Round. Anther color: Close to 145D. Pollen             amount: Scarce. Pollen color: Close to 145D. Pistils: Pistil             quantity per flower: One. Pistil length: About 0.5 mm to             1 mm. Stigma shape: Two to three-lobed. Stigma color: Close             to 146C. Style length: About 0.5 mm. Style color: Close to             146C.         -   Reproductive organs, sterile flowers.—Stamens: Quantity per             flower: About nine to ten. Filament length: About 3 mm.             Filament color: Close to 157D. Anther length: About 1 mm.             Anther shape: Round. Anther color: Close to 157D. Pollen             amount: Scarce. Pollen color: Close to 157D. Pistils: Pistil             development has not been observed on sterile flowers of the             new Hydrangea to date.         -   Seeds, only produced by fertile flowers.—Quantity per             fertile flower: About 20 to 30. Length: Less than 0.5 mm.             Diameter: Less than 0.5 mm. Color: Close to 200C. -   Pathogen & pest resistance: Under commercial production conditions,     plants of the new Hydrangea have not been observed to be resistant     to pathogens and pests common to Hydrangea plants to date. -   Garden performance: Plants of the new Hydrangea have been shown to     have good garden performance and to be tolerant to temperatures     ranging from about −38° C. to about 38° C. 

It is claimed:
 1. A new and distinct Hydrangea plant named ‘HP217901’ as illustrated and described. 